(CNN)Each fall, as leaves turn golden and the crisp autumn air carries the scent of pine, Catherine Franssen waits for her husband to bring home the latest pumpkin spice-flavored concoction he has discovered at the grocery store.

"My husband -- whose favorite pie is pumpkin; he'll eat it year-round -- thinks the pumpkin spice craze is funny and brings home all sorts of odd pumpkin spice items to try," said Franssen, assistant professor of psychology and director of the neurostudies minor at Longwood University in Virginia.

"I think I ended up eating the entire box of pumpkin-spiced Cheerios last year after the rest of the family tasted and rejected," she said. "They were pretty good."

Franssen called the current trendiness of pumpkin spice "a fantastic example of the psychology of consumer behavior and fads." She knows that the sweet smell and tantalizing taste of pumpkin spice can trigger a nostalgic emotional response in her brain and the brains of many other consumers, she said.

After all, "this spice blend has been used in popular baked goods for quite some time, but mostly in home-baked goods," said Franssen, who wrote a 2015 blog post in the Huffington Post about the science behind pumpkin spice.

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"Since these are popular spice combinations, it's very likely we would have encountered some or all of them combined in a favorite baked good in a comforting situation, like a family gathering, early in life," she said. "It's not just the pumpkin spice combo but that we've already wired a subset of those spices as 'good' very early in life."

In other words, if the pumpkin spice blend -- or a synthetic version -- that has been added to your favorite food item reminds you of a baking pumpkin pie at grandma's house, then it probably did its job.

What is pumpkin spice anyway?

Most pumpkin spice mixtures don't involve an actual pumpkin. Typically it contains ground cinnamon, nutmeg, dry ginger and clove or allspice mixed together, said Kantha Shelke, a food science communicator for the Institute of Food Technologists and a scientist at Corvus Blue, a Chicago-based food science and research firm.

When many food companies use a pumpkin spice flavor, they often develop a synthetic version with various compounds and aromas designed to trick your brain into thinking you actually consumed a mix of cinnamon, nutmeg and other spices.

Included in many of these synthetic pumpkin spice flavors are top notes that mimic the aroma of butter browning with sugar, which creates an olfactory illusion of a freshly baked pumpkin pie, Shelke said.

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Nonetheless, "history shows that pumpkin spice-like combinations have been used for millennia in various cultures," said Shelke, who is also an adjunct professor of regulatory science and food safety at Johns Hopkins University.

For instance, similar mixtures of spices are used inIndian masala chai and Middle Eastern baklava, she said. These mixtures are often used in celebratory occasions -- most often to ease the digestive impacts of overindulgence, Shelke said.

Yet "in the Western world, the aroma of pumpkin spice immediately transports people to all the warm and friendly times associated with pumpkin pie, holiday gatherings, families, celebrations, treats, sweets ... things that childhood memories are made of," Shelke said. "This is why pumpkin spice latte is trendy."

Pumpkin spice seems to have emerged as a common seasonal scent and taste in the home and food market a couple of decades ago, when spiced pumpkin candles grew in popularity, Franssen said.

"Then, a few high-profile companies, like Starbucks, run some super successful experiments, and then you add in the fantastic marketing strategies, and you've got a fad that turns into a trend," she said.

Starbucks first developed its pumpkin spice latte, known as the PSL, in early 2003. In a news release last week, Peter Dukes, the product manager who led the development of PSL, said, "Nobody knew back then what it would grow to be. ... It's taken on a life of its own."

The marketing behind many pumpkin spice-flavored items, like the latte, condition our brains to expect that pumpkin spice is the flavor of fall and to anticipate the flavor's arrival each season as something comforting, Franssen said.

"We don't have innate odor responses. We learn odors through associations, but the associations we make with pumpkin spice are generally all very positive," she said.

Though, even without the seasonal marketing, the brain has a special response to pumpkin spice when the flavor is mixed with sugar, Franssen said.

Starbucks pumpkin spice latte is the drink that started it all back in 2003.

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Photos:Pumpkin Spice for breakfast, lunch and dinner

Another new entry: Keebler Pumpkin Spice Fudge Stripes cookies

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Photos:Pumpkin Spice for breakfast, lunch and dinner

Country Crock Pumpkin Spice spread

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Photos:Pumpkin Spice for breakfast, lunch and dinner

Califia Farms Pumpkin Spice Latte Cold Brew Coffee

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Photos:Pumpkin Spice for breakfast, lunch and dinner

Pinnacle Pumpkin Pie Vodka

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Photos:Pumpkin Spice for breakfast, lunch and dinner

Kahlua Pumpkin Spice rum

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Photos:Pumpkin Spice for breakfast, lunch and dinner

Ben & Jerry's Pumpkin Cheesecake ice cream

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Photos:Pumpkin Spice for breakfast, lunch and dinner

Chobani Pumpkin Spice Greek yogurt

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Photos:Pumpkin Spice for breakfast, lunch and dinner

Pumpkin spice-type flavor has even made its way into protein powder.

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'Actually, scientifically, kind of addictive'

"When an odor or flavor -- and 80% of flavoris actually smell -- is combined with sucrose or sugar consumption in a hungry person, the person learns at a subconscious, physiological level to associate that flavor with all the wonderful parts of food digestion," Franssen said.

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By combining the recognizable pumpkin spice flavor with sugar, you train your brain and body to remember how delicious the combination is -- and as soon as you smell or even imagine pumpkin spice, your body will have an anticipatory response and crave it, Franssen said.

For that reason, "the pumpkin spice latte is actually, scientifically, kind of addictive," she said. "Not quite the same neural mechanisms as drugs of abuse, but certainly the more you consume, the more you reinforce the behavior and want to consume more."

On the other hand, natural pumpkin spice mixtures without added sugars, fat or salt could offer some potential health benefits if used in a pumpkin soup or to flavor vegetables, Shelke said. Pumpkin is a source of vitamin A, fiber and other nutrients.

"I love vegetables and consume at least eight to 10 servings of vegetables a day. Pumpkin and its cousins show up in my diet regularly and often with pumpkin spice-like spices," Shelke said.

"Spices are powerhouses of phytochemicals -- chemicals that the plant makes to protect itself -- that can afford us health and protectionfrom many health issues. Like with any food, the amount consumed determines the experience and the benefits," Shelke said.

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"All spices come from plants. There are no spices from the animal kingdom," she said. "So, spices are perfect for vegetarians, vegans and those who follow Halal and Kosher diets."

So, if you have the craving, enjoy your pumpkin spice and everything nice.